HDU4010 Query on The Trees(LCT)

#pragma warning(disable:4996)
#include <iostream>
#include <cstring>
#include <string>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;

#define ll long long
#define maxn 350000
#define INF 0x3f3f3f3f

struct Node
{
	Node *p, *ch[2];
	bool rev;
	ll sum, val;
	ll mx;
	ll add;
	int size;
	bool isRoot;
	Node *fa;
	Node(){
		sum = 0; val = 0;
		rev = 0; mx = -INF;
		add = 0;
		size = 0;
	}
	void setc(Node *c, int d){
		ch[d] = c;
		c->p = this;
	}
	bool d(){
		return p->ch[1] == this;
	}
	void upd(){
		sum = ch[0]->sum + ch[1]->sum + val;
		size = ch[0]->size + ch[1]->size + 1;
		mx = max(max(ch[0]->mx, ch[1]->mx), val);
	}
	void revIt(){
		rev ^= 1;
	}
	void addIt(int vx){
		add += vx;
		sum += vx*size;
		val += vx;
		mx += vx;
	}
	void relax();
	void setRoot(Node *f);
}Tnull, *null = &Tnull;

void Node::setRoot(Node *f){
	fa = f;
	isRoot = true;
	p = null;
}

void Node::relax(){
	if (add != 0){
		for (int i = 0; i < 2; i++){
			if (ch[i] != null) ch[i]->addIt(add);
		}
		add = 0;
	}
	if (rev){
		swap(ch[0], ch[1]);
		for (int i = 0; i < 2; i++){
			if (ch[i] != null) ch[i]->revIt();
		}
		rev = 0;
	}
}

Node mem[maxn], *C = mem;

Node *make(int v){
	C->sum = C->val = v;
	C->rev = 0; C->add = 0;
	C->mx = v;
	C->ch[0] = C->ch[1] = null; C->isRoot = true;
	C->p = null;
	C->fa = null;
	return C++;
}

void rot(Node *t){
	Node *p = t->p;
	p->relax();
	t->relax();
	bool d = t->d();
	p->p->setc(t, p->d());
	p->setc(t->ch[!d], d);
	t->setc(p, !d);
	p->upd();
	if (p->isRoot){
		p->isRoot = false;
		t->isRoot = true;
		t->fa = p->fa;
	}
}

void pushTo(Node*t) {
	static Node*stk[maxn]; int top = 0;
	while (t != null) {
		stk[top++] = t;
		t = t->p;
	}
	for (int i = top - 1; i >= 0; --i) stk[i]->relax();
}

void splay(Node*u, Node*f = null) {
	pushTo(u);
	while (u->p != f) {
		if (u->p->p == f)
			rot(u);
		else
			u->d() == u->p->d() ? (rot(u->p), rot(u)) : (rot(u), rot(u));
	}
	u->upd();
}

Node *v[maxn];
vector<int> E[maxn];
int n, nQ;

int que[maxn], fa[maxn], qh = 0, qt = 0;
int wht[maxn];

void bfs()
{
	qh = qt = 0;
	que[qt++] = 1;
	fa[1] = -1;
	while (qh < qt){
		int u = que[qh++];
		for (int i = 0; i < E[u].size(); i++){
			int e = E[u][i];
			if (e != fa[u]){
				fa[e] = u;
				v[e]->fa = v[u];
				que[qt++] = e;
			}
		}
	}
}

Node *expose(Node *u)
{
	Node *v;
	for (v = null; u != null; v = u, u = u->fa){
		splay(u);
		u->ch[1]->setRoot(u);
		u->setc(v, 1);
		v->fa = u;
	}
	return v;
}

void makeRoot(Node *u)
{
	expose(u);
	splay(u);
	u->revIt();
}

void addEdge(Node *u, Node *v)
{
	makeRoot(v);
	v->fa = u;
}

void delEdge(Node *u, Node *v)
{
	makeRoot(u);
	expose(v); splay(u); u->setc(null, 1); u->upd();
	v->setRoot(null);
}

void addPath(Node *u, Node *v,int ax)
{
	makeRoot(u);
	expose(v);
	splay(v);
	v->addIt(ax);
}

ll sumPath(Node *u, Node *v)
{
	makeRoot(u);
	expose(v);
	splay(v);
	return v->sum;
}

ll maxPath(Node *u, Node *v)
{
	makeRoot(u);
	expose(v);
	splay(v);
	return v->mx;
}

Node *find_root(Node *u)
{
	expose(u); splay(u);
	while (u->ch[0] != null){
		u = u->ch[0];
	}
	splay(u); return u;
}

int main()
{
	while (cin >> n)
	{
		for (int i = 0; i <= n; i++) E[i].clear();
		int ui, vi;
		for (int i = 0; i < n - 1; i++){
			scanf("%d%d", &ui, &vi);
			E[ui].push_back(vi); E[vi].push_back(ui);
		}
		for (int i = 1; i <= n; i++){
			scanf("%d", wht + i);
			v[i] = make(wht[i]);
		}
		bfs();
		cin >> nQ;
		int oper, wi, xi, yi;
		Node *nx, *ny;
		while (nQ--){
			scanf("%d", &oper);
			if (oper == 3) scanf("%d%d%d", &wi, &xi, &yi);
			else scanf("%d%d", &xi, &yi);
			nx = v[xi]; ny = v[yi];
			if (oper == 1){
				if (find_root(nx) == find_root(ny)) puts("-1");
				else{
					addEdge(nx, ny);
				}
			}
			else if (oper == 2){
				if (find_root(nx) != find_root(ny) || xi == yi) puts("-1");
				else{
					makeRoot(nx);
					expose(ny);
					splay(ny);
					Node *tmp = ny->ch[0];
					ny->ch[0] = null; ny->upd();
					tmp->setRoot(null);
				}
			}
			else if (oper == 3){
				if (find_root(nx) != find_root(ny)) puts("-1");
				else{
					addPath(nx, ny, wi);
				}
			}
			else{
				if (find_root(nx) != find_root(ny)) puts("-1");
				else printf("%d\n", maxPath(nx, ny));
			}
		}
		puts("");
	}
	return 0;
}